While known devices satisfy, to a greater or lesser extent, the need for monitoring of engine parameters and operating time, they do so in systems that are closely integrated with the engine itself, and which, even when cost effective from a price performance standpoint, add considerable cost to the overall system.
There is a need for a low cost, after-market engine monitor to provide certain basic functions, such as RPM and timing functions. There is a large number of engine driven vehicles and apparatus in existence that have no built in monitoring functions. When these devices are routinely operated by a number of different people, especially in a rental environment, it is difficult to accurately monitor the operation of the engine so that preventive maintenance can be performed in a timely manner. In addition, especially in a rental environment, it is desirable to provide a means for monitoring the running time of an engine, so as to more fairly apportion rental charges based on running time, instead of time of possession. Still further, it is desirable to monitor maximum engine RPM to determine whether an engine has been operated beyond its safe operating range, redline.
An engine monitor that provides all of these characteristics is even more useful if it is small, self-contained, and easily fitted to an existing engine on an existing piece of equipment in a manner that can provide the foregoing functions in a cost effective, low maintenance, easy to install unit.